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Read the page on
amplitude modulation.
Modulation enables low
frequency audio signals
to be radiated long
distances.
This is done by
superimposing the low
frequency audio signal
on the high frequency
carrier wave by the
process of modulation.
The microphone converts
sound waves into
electrical signals ( a
range of 20 Hz to 20
kHz).
These signals are
amplified by the audio
frequency amplifier.
The carrier frequency is
generated by the radio
frequency oscillator.
The audio is
superimposed onto the
carrier by the
modulator.
The low power modulated
carrier is boosted in
amplitude by the radio
frequency power
amplifier.
The aerial produces an
electromagnetic wave
which is radiated into
space. |
